Driving means for phonograph attachments



W. H. GILMAN. DRIVING MEANS FOR PHONOGRAPH ATTACHMENTS.

APPLICATION FILED MAR. 29, 1920- Patented Aug. 16, 1921.

TTO'RNEY partly UNITED STATES PATENT OFFICE.

WILLARD H. GILMAN, OF. NEW YORK, N. Y., ASSIGNORi, BY MES'NE ASSIGNMENTS, JOHN A. MoVICKAlt, OF NEW YORK, N. Y.

DRIVING MEANS FOR PHONOG-RAPH ATTACHMENTS.

Application filed March 29, 1920. Serial No. 369,571;

To all whom it may concern: 7

Be it known that L, WILLARD H. GILMAN, a citizen of the United States, and resident of New York, in the county of New York and State of New York, have invented certain new and useful Driving Means for Phonograph Attachments, of which the followingris a specification.

his invention relates to phonograp-hs and particularly to a driving means for a phonograph attachment and has for an object to provide a simple and inexpensive means for moving a tone arm across the turntable of the phonograph, means for varying the movement-of-the tone arm, means for moving the tone arm over'a greater distance than the driving mechanism moves, a plurality of means for engaging the driving mechanism and means for disengaging the driving mechanism whereby the tone arm may be positioned on the record; other objects will appear from the following specification and drawings in which Figure 1 is a plan view of a phonograph with my invention in place, Fig. 2 is a side elevation, in section, corresponding to Fig. 1 and Fig. 8 is a detail.

The cabinet of a phonograph of the disk type is represented by 11 and the turntable by 12. 13 represents a record which, in this case, is assumed to be of soft wax suitable for both recording and reproducing. This record is made in the form of a ring to pass over the metallicv center plate 14 which is centered on the stem 15 of the turntable. This plate has a raised center 16 with beveled sides 17 ending in the grooved section 18'provided with the spiral shown.

The tone arm 21 ends in 2. turned up section 22 which matches with the elbow 23 to which the horn is attached. This arm swings on the vertical pivot 24 secured in the base 25 attached to the cabinet 11 and ispositioned by collar 26; guide bar 27 may be used to steady section 22 on pivot 24 so that arm 21 moves with complete freedom and with very little friction. The pedestal 28 supported by the base 25 holds the collar 29 upon which the elbow 23 rests, this elbow being secured by the ring 30 so that elbow 23 is free to rotate independently of tone arm 21.

The diaphragm head 31 having the stylus 32 is secured by'a ball and socket joint to the bell mouth of the tone arm as shown; a head suitable for recordin or' reproducing may be used as desired. his invention includes a novel means for moving the tone arm on the pivot 24 causing the stylus 32 to describe an are on record 13 and follow a spiral groove thereon. This means includes the Spiral groove 18 with a pin engaging this groove and suitable connections to the tone arm whereby the latter is moved in con formity with this spiral. The bracket 84 clamped to thetone arm 21 supports the arm Specification of I.etters Patent. I Patented Aug. 163 1921.

35 which ends in a socket upon which. the

hinge member 60 can rotate. This member has an extension 38 which is connected by a spring 39, Fig. 3 with the end collar 37 forming a toggle which, in one position, tends to move this hinge piece down and in the other position holds it up as stop pin 41 ozn extension 38 engages lug 40 secured to 3 Arm 36 is pivoted to swing horizontally by pivot 61 to the hinge piece 60 and normally bears against the stem 15 of the turn- Y table due to the engaging pins in the spiral 18 and the rotation of the turntable. This arm supports the rocker 43 pivoted at 49 and free to swing between the stop pins 46 and 47 This rocker is held in position by spring 45 connected to pin 42 and connecting to arm 36 at 44 thus forming a toggle which holds it rigid against either stop pin.

One end of rocker 43 supports pin 51 and the opposite end supports pin 52, these pins are readily replaceable, by a screw attachment as may be necessary when they wear or require adjustment.

It is well known that the center part of a disk record cannot be used for record ng sound; this invention provides for utlllzing this part as a directing means for moving the tone arm over the sound recording part of the record. The radius of the sound recording part is usually greater than the radius of the center part and in order to take full advantage of the entire sound recording part by this method of drive, means are provided whereby the spiral groove is used a plurality of times in making a continuous spiral on the sound recording part. In Fig. 1 it will be noted that the radius of the spiral 18 is about half the width 33 of the record; when the stylus 32 is p os1t1oned on the outer edge of the record pin 52 engages the outer groove of spiral 18 and as the turntable revolves this pin is gradually moved toward the inner groove of the spiral but before it reaches this point extension 53 engages the incline 17 and tiltsthe rocker 43 over the toggle bringing pin 51 into engagement with the outer groove of the spiral and continuin the drive of the tone arm across the recor pin 51 is adjusted to engage the groove before pin 52 releases thus maintaining a continuous uninterrupted drive for the tone arm.

Just before the stylus has reached the inner edge of the record the stopping mechanism usually provided with phonographs stops the turntable; however, as this is the end of the sound producing record notice is thereby given that the stylus has completed its movement and the driving mechanism can be manually released from the spiral plate.

While'the number of grooves in the spiral 18 per inch is fixed it is possible to vary the number of grooves per inch made by the stylus of the tone arm, this might be desirable, for instance, where the size of the recording jewels in different heads varied or Where the records to .be reproduced had varying numbers of lines per inch. It is apparent that if arm 36 were attached to the tone arm close to its pivot the stylus 32 would make a considerable are for each groove in 18 and, on the other hand, if attached at a radius greater than that through which the stylus moves the-latter will make a closer spiral thanthe grooves in 18. 'An adjustment of this kin may be provided by moving bracket 34 on the tone arm 21, also by moving arm 35 to the extent of the slotted openin 63 through which the clamp screws pass; t is arm for instance, may be moved to the position b in which case arm 36 takes up the position 1 thus making a close groove pn the record. The pivot 61 ofarm 36 permits of this adjustment and the rotation of the turntable holds the arm against stem 15. The toggle secured by spring 39 holds the driving pins in the grooves 18 when in op eration and permits arm 36 to be raisedwhile the diaphragm head is position on the record.

This construction secures a number of important results. The tone arm being entirely su ported by the pivot pin 24 the driving orce from the spiral is merely directive to swing the tone arm in the arc of a circle and therefore operates with very little friction. By adjusting the radius of the driving connection to the tone arm the number of grooves per inch on the record may be varied from the number of grooves on the spiral plate, thus the driving spiral on the plate may have much coarser grooves than the s iral on therecord; this permits the use 0 comparatively coarse driving pins insuring reater rigidlty and longer wear. By using the driving spiral a plurahty of times independent sets of driving pins provides an alternative driving means should either of these get out of order.

Having thus described my invention, I claim:

1. In a phonograph mechanism, the combination of a turntable mounted for rotation, a spiral plate and a record placed on said turntable, a tone arm arranged to move across the face of said record and a plurality of engaging means connecting said spiral plate with said tone arm, whereby said tone arm moves over a wider space on said record than the width of said spiral.

2. In a phonograph attachment, the combination of a turntable mounted for rotation, a spiral plate and a record placed on said turntable, a tone arm arranged to move across the face of said record, an arm connecting said tone arm with said s iral plate a plurality of members associate with sai arm for engaging the spiral of said late and means for bringing one of said mem ers into operative relation with said spiral at a time.

3. In a bination o a turnta le mounted for rotation a spiral plate and a record placed on said turntable, said record being wider than the spiral on said plate, a tone arm having a stylus arranged to move across the face of said record and operably connected with the spiral on said plate and means for automatically making a continuous spiral on said record with a greater number of grooves than the spiral on said plate. 4. In a phonograph attachment, the combination of a turntable mounted for rotation, a spiral plate and a record placed on said turntable, a tone arm, a plurality of pins connecting said tone arm wlth the spiral of said plate, means for movin said tone arm over a portion of said recor by one of said pins and over another portion of said record by another of said pins.

5. In a honogra h attachment, the combination oi a turntal le mounted for rotation a spiral plate and a record placed on said turntable, a tone arm, a plurality of pins connecting said tone arm with the spiral of said plate, means for moving said tone arm phonogra h'attachment, the comover a different portion of said record by 7. In a honograph attachment, the combination of a turntable mounted for rotation,

a spiral plate and a record placed on said turntable, a tone arm, an arm connecting with a said tone arm, a rocker pivoted to said arm,

said rocker carrying a pin at each end to engage the spiral on said plate and a toggle to hold said rocker in position.

8. In a phonograph attachment, the combination of a turntable mounted for rotation, a spiral plate and a record placed on said turntable, a tone arm, an arm pivotally connecting with said tone arm, said arm connecting with the groove of said spiral plate,

1 a toggle spring, said toggle holding said arm in engagement with said groove and also holding said arm released from said groove.

9. In a phonograph attachment, the combination of a turntable mounted for rotation, a spiral plate and a record placed on said 20 turntable, a tone arm, an arm pivoted to said tone arm to swing horizontally and engaging the stem of said turntable, said arm operably connected with the spiral on said plate and means for adjusting the position of said 25 pivot connection on said tone arm.

Signed at New York, in the county of New York and State of New York, this 19th day of March, A. D. 1920.

WILLARD H. GILMAN. 

